The present invention relates to a carbacephem compound having a characteristic electronegative group at the 3-position and a pharmaceutical composition containing the compound.
Heretofore, many patent applications have been filed for the carbacephem compounds, among which those concerning compounds having a 3-positioned substituent include GB No. 2041923A for a compound represented by the formula: ##STR2## (wherein X.sub.a is an amino, azido, or protected amino group; Hal is halogen; R.sub.A is hydrogen or a carboxyl-protective group); EP No. 0014475Al for an optically active isomer of compound represented by the formula: ##STR3## (wherein R.sub.B is hydrogen or an alkyl group; R.sub.C is hydrogen or halogen; R.sub.D is hydrogen or a carboxyl-protective group); EP No. 0014476Al for an optical active isomer of compound represented by the formula: ##STR4## (wherein X.sub.B is a group of ##STR5## or the like; R.sub.E is hydrogen or an alkyl group; R.sub.F is hydrogen or halogen; R.sub.G is hydrogen or a carboxyl-protective group), etc. In addition, a compound represented by the formula: ##STR6## is nominally disclosed in U.S. Pat. No. 4,278,793, column 153.
Compounds of the present invention have a strong antibacterial effect on Gram-negative bacteria and also on Gram-positive bacteria.